Large off-highway vehicles (“OHVs”), such as mining vehicles used to haul heavy payloads excavated from open pit mines, are well known and typically employ motorized wheels for propelling or retarding the vehicle in an energy efficient manner. This efficiency is typically accomplished by employing a large horsepower diesel engine in conjunction with an alternator, a main traction inverter, and a pair of wheel drive assemblies housed within the rear tires of the vehicle. The diesel engine is directly associated with the alternator such that the diesel engine drives the alternator. The alternator powers the main traction inverter, which supplies electrical power having a controlled voltage and frequency to electric drive motors of the two wheel drive assemblies. Each wheel drive assembly houses a planetary gear transmission that converts the rotation of the associated drive motor energy into a high torque, low speed rotational energy output which is supplied to the rear wheels.
In existing OHVs, friction brakes are applied with a fixed braking pressure proportion between front and rear braking systems. Because operating loads in an OHV may exceed one hundred tons, and the gross weight of the vehicle and load may be several hundred tons, this may result in varying wear rates between the front and rear friction brakes, requiring the front and rear friction brakes to be replaced at different times and thereby increasing maintenance costs. Accordingly, it may be desirable to provide a braking system and method that different from existing systems and methods.